Catalyst based on aluminum fluoride for the fluorination in gaseous phase of hydrocarbons

ABSTRACT

A catalyst is disclosed for the preparation of fluroinated or chlorofluorinated hydrocarbons through fluorination or chlorofluorination reactions in gaseous phase, the catalyst comprising aluminum fluoride or fluorinated alumina containing minor quantities of manganese, chromium and preferably also nickel compounds present in quantities corresponding to the following percentages by weight of metal based on the total: from 0.05 to 5% of Mn, from 0.1 to 5% of Cr, and up to 5% of Ni. The manganese, the chromium and (when present) the nickel are at least partially present in the form of halides, and in particular the fluorides, or as oxides or as oxy-halides.

United States Patent [191 Groppelli et al.

[ 51 Jan. 22, 1974 CATALYST BASED ON ALUMINUM FLUORIDE FOR THE FLUORINATION IN GASEOUS PHASE 0F HYDROCARBONS [75] Inventors: Giovanni Groppelli; Vittorio Fattore; Martino Vecchio, all of Milan; Arsenio Castellan, Bollate, all

of Italy [73] Assignee: Montecatini Edison S.p.A., Milan,

Italy 3 [22] Filed: Oct. 7, 1969 [21] Appl. No.: 864,519

[30] Foreign Application Priority Data Oct. 10, l968 Italy 22295/68 [52] U.S. Cl. 252/442, 260/653.7 [51] Int. Cl B01] 11/78 [58] Field of Search 252/442; 260/653.7

[56] References Cited UNITED STATES PATENTS 2,744,148 5/l956 Ruh et al. 252/442 X 3,294,852 12/1966 Vecchio et al 260/653.7

3,342,881 9/1967 Sasakura et al 260/653.7

Primary Examiner-Patrick P. Garvin Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher [57] ABSTRACT A catalyst is disclosed for the preparation of fiuroinated or chlorofluorinated hydrocarbons through fluorination or chlorofluorination reactions in gaseous phase, the catalyst comprising aluminum fluoride or fluorinated alumina containing minor quantities of manganese, chromium and preferably also nickel compounds present in quantities corresponding to the following percentages by weight of metal based on the total: from 0.05 to 5% of Mn, from 0.1 to 5% of Cr, and up to 5% of Ni. The manganese, the chromium and (when present) the nickel are at least partially present in the form of halides, and in particular the fluorides, or as oxides or as oxy-halides.

1 Claim, No Drawings l CATALYST BASED ON ALUMINUM FLUORIDE FOR THE FLUORINATION IN GASEOUS PHASE OF HYDROCARBONS The present invention concerns new catalysts for the fluorination in gaseous phase of halogenated hydrocarbons and for the chlorofluorination of ethylene. These new catalysts are characterized in that they favor the formation of greater quantities of symmetrical compounds or of compounds with a degree of symmetry relatively higher than that of compounds obtained by means of known catalysts. The expression degree of symmetry as employed herein refers to the distribution of the fluorine atoms and it is also understood that a compound not exactly symmetrical, such as CF CI CFCl nevertheless has a degree of symmetry greater than its isomer CF,,- CCl lt is well known. that many metal compounds show catalystic activity in the fluorination with HF in gaseous phase of halogenated hydrocarbons. in particular, there may be cited as examples the British Patent No. 428,361 disclosing halides of Fe, Ni, Co, Mn, Cd, Zn, and Hg as well as many others, including some combinations thereof.

in French Patent No. 1,380,938, the catalytic activity of halides Al, Fe, Cr, Mn and Ni (and of many other metals) in the above-cited reaction is suggested.

What does not seem to be known, however, is' the particular catalytic compositions which are the object of this invention, and which distinguish themselves from other known compositions, amongst others, by its" above-mentioned selective catalytic effect.

The qualities of manganese, chromium and nickel compounds introduced into the present catalytic compositions base on aluminum fluoride must be such-as to fall within the following limits:

from 0.05% to 5% by weight, based on the total of manganese,

from 0.1% to 5% by weight, based on the total, of chromium,

up to 5% by weight, based on the total, of nickel. t

lnstea d of zil uminum fluoridejone may also use alu-;

mina for the preparation of the catalyst describedi herein, the alumina in a subsequent fluorination treat-i ment of the catalytic composition with gaseous HFE being substantially converted into the fluoride. By; using alumina for the preparation of the catalyst one: will have to use somewhat greater quantities of manga-; nese, chromium, and nickel compounds, that is, quanti- E ties towards the higher percentages indicated above.

troduced into the catalytic composition of the present invention based on aluminum fluoride preferably in the form of solutions of their salts or other compounds, such as for instance nitrates and chlorides, which are adsorbed by the aluminum fluoride or by the starting alumina. The composition thus obtained is then dried in an oven at about 150C. I

In the preparation of the catalyst one preferably uses 7 manganese, chromium and nickel compounds in the trogen for a period of from 0.5 to 4 hours, at a temperature between 300 and 550C.

For preparing the catalyst from alumina one requires relatively higher temperatures than in the case of aluminum fluoride. The fluorination is carried out by heating the activated product in a current of gaseous HF, suitably diluted with air or nitrogen or with another inert gas, at a temperature between 200 and 500C.

The dilution of the HF has mainly the purpose of more easily controlling the reaction temperature as well as to avoid local overheating.

The catalyst thus obtained in fine granular form, is particularly suited for use in fluid bed reactors.

The preparation of the catalyst of the present invention will now be illustrated in greater detail in the following Examples 1 and 2. in the-first example the preparation starts from alumina, while in the second example the preparation starts from aluminum fluoride.

The catalyst according to the present invention has proved particularly useful in the following reactions:

a. Fluorination in gaseous phase, with HF, of halogenated ethanes containing at least one chlorine atom, at a temperature between 330 and 500C. in order to obtain fluorinated or chlorofluorinated ethanes in high yields in the form of compounds having a high degree of symmetry with respect to the fluorine atoms, and in particular, the fluorination of CF ClCFCl obtaining high yields of the symmetrical CF ClCF Cl product and a reduced isomerization of the starting material into CF3CCI b. Chlorofluorination of ethylene in gaseous phase with a C1 HF'mixture in the presence of recycled halogenated hydrocarbons, at a temperature between 330 and 500C. in order to obtain prevailingly C F,Cl and C F Cl with high percentages of isomers having a high degree of symmetry, that is, CF Cl-CF Cl and CF ClCFCl d. Disproportioning reaction of CF ClCFCl in gaseous phase, at temperatures between 330 and 500C. with the formation of large quantities of the symmetrical compound CF ClCF Cl and of very small quantities of CF -CCI isomer.

It must be borne in mind that above the indicated limit of 500C. the selectivity of the catalyst in promoting the formation of symmetrical products decreases with increase in temperature.

The use of the catalyst according to the present invention in the above cited reactions is illustrated hereinafter in Examples 3 to 10, which, however, are not to be taken as limiting but rather as illustrative.

EXAMPLE 1 PREPARATION OF THE CATALYST STARTING FROM ALUMINA 4. upon X -Tay analysis it turned out to consist of 'y-AlF- with the presence of B-AlF- It showed the following granulometric distribution, determined with screens of the Tyler series 351 g of a 50% solution of Mn(NO,-,) are mixed with 106.8 g of NiCl '6H O and 67.5 g of CrCl '6H O and with little water at room temperature. The solutuion thus obtained is diluted to a volume of 370 cc corresponding to the total volume of the pores of the alu- Y ab'ovefl mina to be impregnated. This solution is then slowly s 120 1 1 M s 23 270 325 325 5.2 14.9 13.4 16.2 18.8 12.8 12.8 5.8

poured onto 1,000 g of Ketjen grade A alumina kept A under slow continuous stirring both during impregna- On 500 g of this aluminum fluoride was poured under tion as well as during a subsequent period of 2 hours. continuous slow stirring the solution of active elements. The solution is then left to rest for 4 hours and is then ID This solution of active elements was prepared by disdried in an oven for 12 hours at 150C. solving 42.6 g of NiCl,' 6H O, 26.9 g ofCrCl -6H O and 1 CHEMICAL AND PHYSICAL CHARACTERISTICS oi THE ALUMiNA US in spheroidal shape 280 m lg 0.45 cc/g 0.92 g/cc Alumina Ketjen grade A:

surface area volume of pores apparent specific weight Mean composition:

N3 0 0.06% so 1.80% so. 0.66% Fe 0.015%

Loss of weight after calcinatio n at450C. for 4 hours=20% 'l he gnmulornetric distrihution f alumiria deic rmincd b y means of screens (sieves) of the Tyler series and was:

MCShl 80 100 i l 1 50 n 200 270 i 325 above 325 h V i The impregnated alumina is then poured into an Inconel reactor of 5 cm diameter in which the activation, with a fluidizing velocity of about 9 cm/sec., is carried out with air and is then followed up by the fluorination quantity of water heated at 80C. and by diluting the resulting solution up to a volume of 80 cc which corresponded to the total volume of the pores of the aluminum fluoride to be impregnated. The whole was then with hydrofluoric acid according to the following pro- 30 cedures: left to rest for 4 hours and was then dried for 12 hours Activation at 150C.

The activation was carried out with air in an lnconel reactor with a diameter of 5 cm, at a fluidizing speed of about 9 cm/sec., and was then followed by the fluorination with hydrofluoric acid according to the following procedure:

Activation The mass was heated up to 300C. in a stream of N then maintained at this temperature for 1 hour and, tinally, cooled down from 300 to 200C. in 30 minutes. still in a stream of N Fluorination The mass was heated up to 420C. in a stream of N for a period of 90 minutes. Thereupon, and for a period of 90 minutes, a stream of N HF (total: 90 g of HF) at 420C. was passed over the mass. Finally, it was cooled down from 420 to 200C. in 60 minutes in a stream of nitrogen.

The mass is heated in an air stream for 4 hours from C to 500C. [t is kept at 500C. for minutes and is then cooled down, still in an air stream, from 500C. to 200C. in 2 hours.

Fluorination The mass is heated in an air stream up to 250C and is then introduced for atoms into a mixture of air and HF. The total quantity of HF amounts to 1,450 g. Thereafter the mass is heated up from 250 to 420C., still in an air stream. At 420C. the mass is further fluorinated for 4 /2 hours with a mixture of air and HF. The quantity of HF introduced into the reactor amounts to 600 g.

Finally, the mass is cooled down from 420 to 200C. in an air stream only.

EXAMPLE 2 PREPARATlON OF THE CATALYST STARTING FROM AlF For this test the catalyst was prepared by pouring the solution of active elemerits onto aluminurn fluoride having the following chemical and physical characteris- EXAMPLE 3 FLUORINATION 1N GASEOUS PHASE OF CF ClCFCl The fluorination reaction was carried out in a nickel content i fl i amounting to 641% reactor containing a Catalyst based on aluminum fluocontains the following elements, determined by emisride with Varying quantities of manganese Chromium Sion Spectrograph; nickel, with an equimolar ratio of the HF and CF Cl--CFCl reactants. The reaction products were washed with water and 3: 3 55 caustIc soda and were then condensed. The composI- tion of the mIxture was determined by chromatography Ga Fe Mg and, with regard to the isomers, by means of IR. ab- 0.00s7% 0.018% 0.00967: sorption spectra Mn Mo Ni Table 1 records the results, after 5 hours running, of M0487 00057 the tests carried out both with the catalyst of the pres- Si Na Pb ent invention as well as with different other catalysts. 0.060 .0 000W! in order to demonstrate the characteristic results 68.5 g of a 50% solution Mn(N :a)2 in the-minimum V achieved by the present invention.

EXAMPLE 4.

well as in the presence of other different catalysts for purposes of comparison. The results after about 25 hours running are recorded in Table 2.

These tests were carried out in a nickel reactor containing the catalyst based on aluminum fluoride with varying quantities of manganese, nickel and chromium, feeding in the reactants C H C1 HF together with recycle products (i.e., chlorofluorinated hydrocarbons) whose composition is reported in Table 3.

The reaction product was subjected to distillation. The tail fraction was recycled back into the reactor, while the head fraction was composed of a mixture of C F CLC F C1 and C F C1 Both the composition and the ratio between the various isomers are recorded in Table 2.

EXAMPLE 5 DlSPROPORTlONlNG REACTION AND lZOMERl- ZATlON OF CF ClCFC1 The CF C1CFC1 in the gaseous state is passed through a glass reactor containing the catalyst according to the working conditions indicated in Table 4.

The reaction products, after 5 hours running, were directly conveyed into a chromatograph in order to determine their composition. The results recorded in Table 4 show how effective is the contemporaneous presence of manganese, chromium and nickel in the aluminum fluoride in favoring the disproportioning reaction of CF Cl-CFCl thereby forming symmetrical products, and in reducing the isomerization reaction to yield the undesired CC1 ,-CF;,.

EXAMPLE 6 Through a nickel reactor containing fluorinated alumina impregnated with 0.8% of Mn, 1% of Cr and 2% of Ni, there was passed a stream of CF Cl-CFCl at a temperature of 450C. After a run of about 100 hours the temperature was decreased to 400C. and the composition of the gases flowing out of the reactor was determined. Table 5 records all the reaction conditions of this test as we'll'as the products obtained.

during the same run.

6 EXAMPLES 7 and 8 Using the same catalyst as in the preceding example, two fluorination tests in gaseous phase were carried out on CF C1CFCl in the same equipment used in Example 3. Table 5 records the reaction conditions and the products obtained in this test.

' EXAMPLE9 A continuous chlorofluorination test in gaseous phase on ethylene was conducted in the presence of a catalyst consisting of fluorinated alumina impregnated with manganese, chromium and nickel nitrates. The reaction was conducted in an lnconel reactor provided with a thermometer sheath of A181 316, according to the same procedures as described above in Example 4. The test was carried on for about 210 hours at 400C. and subsequently for another 300 hours at 450C.

Table 6 records the conditions used and the products obtained at various times after start of the run. Table 7 records the corresponding composition of the recycle EXAMPLE 10 2.164 g of fluorinated alumina were impregnated with a solution consisting of 64 g of MnCl '4H O and 129.8 g of CrO and were then dried in a fluid bed at 100C. The mass was then kept for 12 hours in an oven at 150C. 1

The impregnated fluorinated alumina was then loaded into a nickel reactor and was heated up to 300C. in a stream of N for 2 hours. Thereafter the temperature was increasedto 450C. and a mixture of air and HF (40% of'HF) was fed in for 2 hours.

Thereupon the temperature was raised to 500C. and for 14 hours there was passed through the reactor a stream of CF Cl-CFC1 After this period the temperature was reduced to 400C. and the composition of the gases flowing out of the reactor was determined.

Table 8 records the reaction conditions and the products obtained from this run.

After a further treatment at 500C. for further 26 hours, the conversion of the CBCl-CFCI at 400C had not varied.

From the foregoing, it is quite evident how good the stability of the catalyst is even at 500C.

The catalyst used at the above indicated temperatures appeared to be gray in color.

TI'ABIE 1 TEST No. 1 2 3 4 5 6 Catalyst A1F AlF AlF A1F AIF All-" Ni 7: 0 2 2 0 2 2 Cr 7: 0 0 1 O 1 1 Mn 7: 0 0 0 0.5 l 2 Reaction temp. in C. 400 400 400 400 400 400 Contact time, in seconds 3 3 3 3 3 3 Conversion of HF. 7: 83 86 79 50.8 42 31 Com. of CF- .ClCFC1. 7c 96 94 83 50.5 31.8 Net yields. 7:

in CF CF CI 16 31 18 5.5 3.4 0.1 in CF;,CFC1, 48 26 2O 41 9.5 2 in CF C1CF,C1 8.5 16 46 39.5 77.5 88.5 in CF;,CC1;, 23 16 7.7 6 l 0.1

(+) The difference between these totals and 100% is for the most part constituted by C,F,C1 (mixture of isomers) TABLE 2 TEST No. 1 2 3 Catalyst:

Ni '7: 2 2 Cr 0 0 1 Mn 7r 0 0 2 Reaction temp. C. 400 400 400 Contact time in sec. 1.7 1.5 3 Cl lHFlc H 6.1/4.6/1 5/4.4/1 5.3/5.3/1 Recycle lC H /1 10/1 10/1 Conversion of HF, 86.3 88 61.6 Net yields,

in C,F .,Cl 2.4 1.8 traces in C E CI 80 74.1 19 in C F Cl 16.4 23.9 81 Selectivity:

CF,C1-CF Cl/C,F C1 ll 24 77 CF C1-CFCl /C F C1 56 97 TABLE 3 TEST No. l 2 3 Composition in the recycle, in by weight C F CI, 0.5 0.5 traces CF;.-CC1 11.4 17 1 CF C1-CFC1 13.4 14 31.3 C- FCL 0.7 1.4 0.7 C HCL, 1.5 0.8 1.6 z a q 22.4 23.6 27.4 C-,Cl. 43.5 31.2 30 C FCI, 5.4 7.5 6.9 C CL, 1.3 3.3 1.2

(I in test .1. the (.,1-'.,('l is made up 01 of the symmetrical isomer.

TABLE 4 TEST No. I 1 2 3 4 5 6 7 Catalyst Cr 71 2 1 l 0.5 Reaction tcmp., "C 400 400 400 400 400 400 400 Contact time (sec) 3 3 3 3 3 1.5

3 Conversion 99% 97% 99% 67% 37% 31.5%

91% Net yield in C-,F C1 4.6% 14.8% 12.7% 3.6% 3.2% 0.6%

4% in C F CI 23.7% 13.9% 17% 41% 45% 37.4%

31% in CF CCl 32.9% 27.9% 28% 7% 0.1% 14.5%

21% in CgFgCl; 32.8% 43.9% 42.3% 49% 51% 43.5%

('1 ln tests 5 and 6. the C,F C1, consists prcvuilingly of the CF,C1 CF,C1 isomer. In test 7, the C F Cl consists to the extent of 33% of the CF2C1CF2CI isomer.

TABLE 5 EXAMPLE 6 7 8 disproportioning fluorination fluorination Catalyst Ni 2 2 2 Cr E 1 1 1 .\ln 0.8 0.8 0.8 Reaction temp.. C. 400 450 400 Contact time. sec. 3 3 3 HFIC F CL, 1 1 Conversion of HF 35 24.2 Conversion ofCF. .C1CFC1 41.5 37.4 24.8 Net yield.

in CF;,CF. .C1 0.6% 0.8% 0.2% in CF,CFC1. 16.3% 5.4% 3.2% in CF Cl CF CI 30.5% 89% in CF .,CC1 9% traces traces in C,F,Cl 40.2% 8.4% 7.2%

TABLE 6 Hours after start 110 210 251 466 utnlynt Ni 2 2 l 2 Cr I 1 I I Mn 0.8 0.8 I 0.8 (18 Reaction temp. C 1 400 400 450 450 Contact time, sec. 3 3 3 3 CI.,/HF/C H 5.2/4.9/1 5.2/7/1 5.3/5.2/1 5.3/4.95/1 Recycle/( H 10/1 10/1 10/1 10/1 Conversion of HF 63 43 66 64 Net yield in:

C F -,C1 0.1% 0.2% 0.2% 0.1% C. .F C1. 3.1% 5% 33.5% 20.8% C. ,F C1 96.4% 94.7% 65.5% 78.4% Selectn CF C1CF C1/C F;Cl I00 82 83 58 63 CF C1-CFCI /C F Cl v V 100 99.15 99.4 95.7 95.3

TABLE 7 Hours after start 1 10 210 251 466 Recycle composition '7: by weight C1 0.1 0.1 0.2 0.1 CF CCL, 0.4 0.4 2.3 2.1 CFgCl CFCl; I I 55 8 55.6 51.7 43.5 C FC l traces traces 0.5 1.0 C,1*1C1 traces traces traces traces C- F Cl 32.4 35.0 28.5 29.20) C CI 2.2 2.4 10.6 16.4 C FCl 6.7 5.9 5.2 5.4 C Cl 0.4 0.6 1.0 2.3

("J The C,F,Cl consists to the extent of 72.4% of the symmetrical isomer.

TABLE 8 l. A catalyst for the preparation of fluormated hydrocarbons by fluorination or chlorofluorination Dis r0 ortionin reaction of CF C1CFC1 p p g 2 2 reactions in gaseous phase, consisting essentially of ggfig g g gp E aluminum fluoride containing manganese, chromium Conversion CFZCLCFCE, 1 and preferably also nickel, essentially in the form of Net yield in: halides, oxides or oxy-halides, wherein the quantities ga f of those metallic compounds correspond to the CFZCl-CFZCl 33.8% following percentages by weight of metal based on the 85 40 total: from 0.05% to 5% of Mn, from 0.1% to 5% of Cr, and up to 5% of Ni.

What is claimed is: I 

